Semiconductor devices, in particular, power semiconductor devices such as field effect transistors (FETs) and insulated gate bipolar transistors (IGBTs) are widely used in a broad field of applications such as, for example automotive and industrial applications. Attempts are being made to increase the performance of semiconductor devices. For example, attempts are being made to increase the performance of IGBTs by reducing the width of body regions or mesas being adjacent gate trenches in an IGBT. Accordingly, it is desirable to provide a method, by which mesa structures may be defined in a homogeneous manner, the mesa structures having a small width.